Deformed ring pipe joint



unions.

United States tent O1 3,233,926 DEFORMED RING PIPE JOINT BernhardWalterscheid-Miiller, Lohmar, Germany, assgnor to .lean WaiterscheidK.G., Siegburg- Lohmar, Rhineland, Germany Filed Jan. 8, 19.63,-Ser. No.250,134 Claims priority, application Germany, Jau. 9, 1962, W 31,437, W31,438; Feb. 7, 1962, W 31,636 6 fClaims. (Cl. 285-341) Theinvention.relates` to pipes and particularly to pipe According totheinvention a screwed pipe union with a metal packing'ring, having thepressure faces of the union bearing on sloping, conical faces of thepacking ring and causing radial contraction of the ring against thesurface of the pipe, is provided in which each of the threaded parts hasat least one annular ridge, formed by the junction of two surfaces,projecting towards the packing ring, and the packing ring hassaw-tooth-shaped ribs on its inner wall, at least at each end, so thatwhen the threaded parts are screwed up, the ribs penetrate radially intothe surface of the pipe, without material deformation of the packingring.

The device according to the invention differs from the existingso-called cutter rings, the front parts of which are provided withy acutting edge, which is pressed axially against a concave conicalpressure surface and so isforced deeply into the surface of the pipe. v

The invention has among its objects to enable a pipe to beso well sealedand so firmly gripped that the pipe will burst under high pressurebefore the union will give way.

A further purpose of the invention is to ensure that the annular ribs onthe packing ring shall penetrate slightly into the surface of the pipeand shall form a barrier at each end, with respect to the longitudinalaxis, while being capable of withstanding high axial pressures.

The invention has among its further objects to prevent the turning ofthe packing ring while the screwed bushing is being tightened. Finally,the invention provides for the design of the packing ring to be suchthat a distinct torque resistance is felt when one tightens the screwedbushing, from which one can judge that the deformation of the packingring is complete and the seal satisfactory. A particular advantage ofthe' invention is that the pipe union can also be used for sealing pipesof all kinds made of plastics.

The invention is diagrammatically illustrated by way o f 'example in theaccompanying diagrammatic drawings in which FIGURE 1 'is a longitudinalsection through the upper part of a screwed pipe union according to theinvention.

FIGURES 2 and 3 are longitudinal sections showing the initial and finalstages of tightening in an alternative embodiment of the screwed pipeunion having a packing ring with special grooves or knurlings.

FIGURE 4 is a longitudinal section of the construction illustrated inFIGURE 1 but with special packing ring.

FIGURE l of the drawings shows a packing ring 3 in longitudinal section,with the surrounding members of the pipe union, 1 and 2. The pipe unionmember 1, which is in the form of a screwed bushing, has an annularridge 4 formed at the junction of two pressure faces 5. As the screwedbushing 1 is tightened, this annular ridge 4 rides 3,233,926 PatentedFeb. 8, 1966 ice up against the conical face 6 of the packing ring 3 andcauses radial deformation of the packing ring 3. Ribs 7, provided in theinterior walls of the packing ring 3, are pressed into the surface ofthe `pipe 9 radially and without axial displacement. Angle oc, betweenthe conical faces 5 and 6, should be as acute as possible, since thematerial of the packing ring 3, after deformation, is intended to offernoticeable resistance to the tightening of the screwed bushing 1.

On the counter union member 2 an annular ridge 8 is provided which bearsagainst the conical face 14 of the packing ring 3 at a position whichensures that'the ribs 7 shall be pressed into the face of the pipe 9 atthe end of the pipe.

In the examples shown in FIGURES 2 and 3, the same face of the ring 14has grooves or knurlings, 10 and 11, running parallel to the axis. Theseknurlings 10 and 11 should be so disposed that the annular ridge 8presses into face 14 of the packing ring below knurling 11, but, asdeformation proceeds, a tight closure is formed between the knurlings10/11 and the pressure face 16 of the counter union member 2. Once thesetwo faces are in contact, they form an effective brake on any tendencyof the packing ring 3 to be carried round with the screwed bushing 1 incourse of tightening.

Between the knurlings 10 and 11 is a smooth surface 12, which forms abreak in the axial knurlings and is a further protection against leaks.This additional seal becomes effective as soon as the edge 13 meets thesurface 12. However, even if, for example, because of some disconformityin the outside diameter of the pipe, the ring has to be subjected toextra deformationA inwardly, so bringing the knurlings 10 partly orcompletely under the sloping face 16, the surface 12 preserves itsadditional sealing function, since the grooves in 10 and 11 do not runinto surface 12, but are blocked off from the surface 12 by the materialthrown up.

In any event, by reason of the existence of the two edges 8 and 13, a rmgrip and a reliable seal will be ensured. Angle IS, between the faces 16and 11, should be as acute as possible, say 1 (for clarity the angle isshown enlarged in the drawing) so that the effect aimed at by theinvention may be obtained without the need for relative axial movement.

FIGURE 3 shows the packing ring 3 after deformation. As can be seen, theedge 13 has come into contact with the smooth surface 12 betweentheknurlings 10 and 11. Though only a few of the ribs 7 in the innerwall are shown the invention envisages the provision of as many ribs 7as desired, but it is advisable, for practical reasons, for these to becontinuous. n

FIGURES 2 and 3 also show how the face 14 of the packing ring 3 isextended beyond the endl of the pipe 9 to form an extension 15 in theshape of a hollow cone. This slope, which is highlyadvantageous from themanufacturing standpoint, ensures that the packing ring 3 can be slippedover the pipe 9 from one end only, since the diameter of ring 3 alongextension 15 is too small to enable this part to be fitted over thepipe. The extension 15 constitutes an effective stop for the pipe sincethe packing ring 3 can be drawn only so far onto the end of the pipe,before the pipe end cornes up against the inside of extension 15. Thefitter then knows that the packing ring 3 is in the right position,without having to bother with measurements.

-for lmanufacture. .matter -of degree andareof no consequence whateverin in the construction shown by way of example in FIG- URE 4, theconical surfaces 6 and 14 of the packing ring 3 have been extendedfarther towards the middle, until at .'17 they either meet abruptly orrun olf into a short cylindrical portion, such as may result, forexample, from slight `variations in course yof manufacture. Thepacking-ring material numbered 18, which in longitudinal section issubstantially cone-shaped, is additional to that which appears inFIGURE 1. It might be considered that the use of :extra .material shouldbe avoided, since it results .in a `slight increase in thedimensions ofthe screwed `ring joint, a'besideswhich .the packing .ring requires morematerial These-drawbacks, however, are all a ffthe face of theaddedadvantageof the construction, namelly that this. additional material l13has the effect `of limit- Ying ,the tighteningof .screwed bushing 1 andlso preventing possible over-tightening. There yis an acute anglevbetween thepressure surfaces and .facesand :14.k This ensuresthat theannular ridge kfwillcertainly be the first '.part to bezforcedinto thefaces 6 .and 14 of the packing :ring.3. Hence, even allowingifor anytolerance variations, it is certain that the ribs 7 will tirstof allbeforced ,into the surface of the pipe 9. lt is only when-this has takenplace that 'the packing-ring material 18 will be brought into .:play;vrthis material .will then offer quite ,appreciable resistance .to thefurther tightening of the screwed vbushing 1, and the 'fitter willtherefore know that v`the .ipackingzring 3'has1undergonezthe resquisitedeforma- .iOn.

The invention vbenefits materially if the packing ring A3 is superciallyhardened, .and lmore particularly carburid. Though this appearscontradictory, because case-hardening, as such, presents considerableresistance :to the deformation of the packingring 3, it is neverthe-`:less consideredthat ,operation is as indicated.

fIn fact, however, in the initial stage of deformation,

a high4 pressure per unit area is. exerted. What is importantis thatthissurfacepressure by the annular ridges 4 `and-8 maybe. regarded as beingpropagated cone-fashion through thematerial of the packing ring 3. Asonly the surfaces at 6 and 14 of the packing ring 3 are hardened,

,-.the main bulk of thepacking ring 3 is still capable offplas- ,ticdeformation. .Under theiniiuen of the heavy surface pressure per unitarea exercised by therscrewed bushing 1, the packing ring 3 .asa'wholegives way, with the .result thatatheribs 7 in the-innerwall ofthe packing ring '3. pressthemselves into-theisurface ofthe pipe .9 withconsiderable force and there create firm seals and anchorages.

As the screwed bushing 1 is further tightened, the annular ridge 4rotatesin relation, to the packing-ring .face '6.

This relative movement results in the v ridge 4.'simply.-gr-indingfdownon the .face 6 of the packing ring 3 and v.thusgradually forcing the ribs'7, on the inner wall, into thesurfacefof-thepipe 9.

If a packing ring 3, according to the invention, isicut open, afterdeformation, Aalong its longitudinal axis, it .will'be found that atleast four of the ribs 7 provided on thel'face of the `packing ,ring 3will have been forced radially into the surface of thel pipe 9, withoutaxial displacement, and will have left unbroken circular grooves behind.The depth of these circular grooves in the surface of the pipe 9decreases towards the middle `of the packing ring'3. At the end of thepacking ring 3 which lies towards the counter-union member 2, the ribs 7of lthe packing ring 3 will also have been forced into 'the'surfaceofthe pipe-9, though perhapsl not in the same numbers as-atV the endthat lies nearer the screwed bushing 1. It is therefore apparent thatthe essential operation is :not so much. to Y.drivethematerial of thepacking ring-3 so that it swells to some extent, in order that it `maylbe contracted and compressed `between a pressure surface 5 of thescrewed bushing 1 and the surface of the pipe 9, but rather that theannular ridge 4 of the screwed bushing ll and the annular ridge 8 of thecounter-member 2 shall transmit force, radially or at a slight angle,through the material of the packing ring 3, and directed on to the ribs7 on the inner wall of the packing ring, so that these ribs may beforced deeply enough into the surface of the p pit must be stressed,however, that the depth of this penetration is appreciably less thanwith existing cutter rings. In the device according to the inventionl noridges are thrown up. It is therefore possible to splitropen the usedpacking ring 3, and .remove it from the end of the pipe, and thentoKmake a fresh union 'with thepipe 9, without cutting the lendback, bythe use fof afresh packing ring `v3. This.. is not usually possible with'unions made With cutter rings.

All that a cutter ring does is to produce a radial constriction of oneend of a packing ring/thatl is moved axially, so that the cut edge maypenetrate the surface of the pipe axially and radially. At-the end Vofthe packing ring lying towards .the yscrewed bushing, onlthe `otherhand, no seal iscreated. 'f

lWith the device according to the invention, however, the -packing ring3 is Vcaughtbetween two annular ridges, 4 and 8,--fron1l which forces ofaction andreaction are thereupon exerted, through the .material of thepacking ring 3, on the inner face of the ring, in order that the ribs 7lon this innerfaceshall be forced into the surface of the ipe 9v at bothends of the .packing ring 3.

lIt is of interest to note that a considerable "increasein efficiency,of the sealing produced and the anchoring of the pipe 9, can be obtainedby superlicialhardening, and more particularly carburising, of theentire surface `of the packing ring 3. Here again, the invention pointsto the advantage-of.havingthe packing ring made of tempered vbeingformed as a pair of angularly adjoining frustoconical surfaces lying atdierent angles with respect to the longitudinal axisof said pipe so asto form a respective annular edge of obtusely angular cross-section atthe junction betweenthe frustoconical surfaces of each abutment face,vthe frustoconical surfaces of each abutment face including a-firstconical surface overlying said packing ring and lying at an angle withrespect to said pipe axis lessf than that of the respective beveled endface and asecond frustoconical surface extending axially inwardly fromsaid first frustoconical surface and lying at an angle .with respect tosaid pipe ,axis larger than that of the .respective beveledfend face,said packing ring having its major portion formed of a softer materialthan said clamping members, saidv packing ring being formed withY.relatively closely axially spaced annular inwardly directedcuttingteeth along said annular surface for penetrating said peripheralsurface upon threaded interconnectionof said members whereby -saidannularV edges bite into said beveled end face as saidmembers arerotated relatively A,and force material ofsaid packing ring between saidfirst and second frustoconical surfaces and said pipe until said.second'frustoconical surfaces are brought into extended surface contactwith said packing ring.

ZVA compression tting as defined in claim 1 wherein -at-leastfpartofl'said ring consistsofhardened steel.

3. A compression fitting as dened in claim 1 wherein eters of saidsecond frustoconical surfaces for limiting at least part of at least oneof said beveled end faces is axial intertting of ysaid members beyond apredetermined knurled in a region engageable by the respective abutmentpoint. face for entrainrnent thereby to prevent rotation of said packingring as said members are rotated relatively. 5 Refeellces Cied by theEXillIliel 4. A compression tting as deiined in claim 3 wherein UNITEDSTATES PATENTS the knurled portion of said one of said beveled end facesis an ann-ulus whose radius is greater than that of the Egg? annularcutting edge of the respective abutment face. ,3214 2/1941 L y 285 3415. A compression fitting as defined in claim 4 wherein ,2"3 amont I 102,490,620 12/1949 Cole.

two such knuiled annuluses are axially spaced along said 613,959 10/1952Richards@ 285 341 one of said beveled end faces and have a relativelysmooth annular band between them, said band having a radiussubstantially equal to that of the respective annular 2,641,489 6/ 1953Hedberg. 2,934,362 4/ 1960 Franck. 3,040,284 6/ 1962 Connell.

cutting edge. 15

6. A compression fitting as defined in claim 1 wherein 3107108 10/1963Greene 285-341 said beveled end faces merge at a median transverse planeCARL W TOMLIN Primary Examine', of said packing ring and form a ridge atsaid median plane whose diameter is greater than the maximum diam-EDWARD C- ALLEN, Examiner

1. A COMPRESSION FITTING ADAPTED SEALINGLY TO ENGAGE A PIPE HAVING ACLOSED PERIPHERAL SURFACE, SAID FITTING COMPRISING A RING OF RELATIVELYHARD BUT DEFORMABLE MATERIAL SURROUNDING SAID PIPE AND HAVING AN ANNULARSURFACE JUXTAPOSED WITH THE PERIPHERAL SURFACE OF SAID PIPE AND HAVING APAIR OF BEVELED END FACES; A PAIR OF THREADEDLY INTERCONNECTED CLAMPINGMEMBERS SURROUNDING SAID PIPE AND HAVING RESPECTIVE ANNULAR ABUTMENTFACES ADAPTED TO BEAR AGAINST SAID BEVELED END FACES WHEN SAID MEMBERSARE THREADEDLY DRAWN TOGETHER, EACH OF SAID ABUTMENT FACES BEING FORMEDAS A PAIR OF ANGULARLY ADJOINING FRUSTOCONICAL SURFACES LYING ATDIFFERENT ANGLES WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID PIPE SOAS TO FORM A RESPECTIVE ANNULAR EDGE OF OBTUSELY ANGULAR CROSS-SECTIONAT THE JUNCTION BETWEEN THE FRUSTOCONICAL SURFACES OF EACH ABUTMENTFACE, THE FRUSTOCONICAL SURFACES OF EACH ABUTMENT FACE INCLUDING A FIRSTCONICAL SURFACE OVERLYING SAID PACKING RING AND LYING AT AN ANGLE WITHRESPECT TO SAID PIPE AXIS LESS THAN THAT OF THE RESPECTIVE BEVELED ENDFACE AND A SECOND FRUSTOCONICAL SURFACE EXTENDING AXIALLY INWARDLY FROMSAID FIRST FRUSTOCONICAL SURFACE AND LYING A AN ANGLE WITH RESPECT TOSAID PIPE AXIS LARGER THAN THAT OF THE RESPECTIVE BEVELED END FACE, SAIDPACKING RING HAVING ITS MAJOR PORTION FORMED OF A SOFTER MATERIAL THANSAID CLAMPING MEMBERS, SAID PACKING RING BEING FORMED WITH RELATIVELYCLOSELY AXIALLY SPACED ANNULAR INWARDLY DIRECTED CUTTING TEETH ALONGSAID ANNULAR SURFACE FOR PENETRATING SAID PERIPHERAL SURFACE UPONTHREADED INTERCONNECTION OF SAID MEMBERS WHEREBY SAID ANNULAR EDGES BITEINTO SAID BEVELED END FACE AS SAID MEMBERS ARE ROTATED RELATIVELY ANDFORCE MATERIAL OF SAID PACKING RING BETWEEN SAID FIRST AND SECONDFRUSTOCONICAL SURFACES AND SAID PIPE UNTIL SAID SECOND FRUSTOCONICALSURFACES ARE BROUGHT IN TO EXTENDED SURFACE CONTACT WITH SAID PACKINGRING.